Encapsulating a crawl space is a common way to deal with moisture or flooding. It is also an easy way to quickly get control of the air quality in the home and lockout rodents and insects. When you’re thinking about “green-ovating” your home, or simply getting control of the moisture or humidity, when you have a crawl space, you must encapsulate.
Encapsulation does a great deal for the crawlspace and for the home above.
What the process is and what it does
The practice of encapsulating or “sealing off” a crawlspace is done to lock out moisture and cut off the connection between moisture, water and the joists of a home. By running a vapor barrier down the walls of a crawl space to completely cover the floor, you essential separate the outside from the inside of the home.
This vapor barrier will be the flexible membrane between the walls and floor and the rest of the home. A properly designed vapor barrier will limit the transfer of moisture through it while regulating the speed at which air will naturally pass through. This helps to limit and control the amount of moisture that will find its way into the air space and completely segregate liquid water and direct it to a sump location.
5 helpful tips when having a Vapor Barrier installed in your crawlspace:
1.) Not all vapor barriers are made for this task – careful. There are many products out in the world that claim to be able to fully encapsulate a crawl space. Make sure that your vapor barrier has a low “perm” rate and that it is at least 14mil thick. If you’re planning to use the space for storage make sure that a flexible sub-flooring product is also placed on top of the vapor barrier to protect it.
2.) Cover the walls too – all too often contractors forget to also encapsulate the walls of the crawl space when installing a vapor barrier. This can still allow water and moisture into the basement and therefore render the whole project useless. Take care to make sure it’s installed properly.
3.) Don’t use sprays. – Sealants and sprays aren’t designed to be applied on the interior of the basement. They are good in many circumstances as the “first line of defense” but as the last, they can’t hold the pressure and moisture trapped in a wall.
4.) Install a sump and a dehumidifier – to totally control the moisture level in the crawl space it’s imperative that you have a sump pump and a dehumidifier installed. Moisture will still exist, although not to dangerous levels, but a sump will remove any liquid water your encapsulation traps, and the dehumidifier will deal with any residual moisture that naturally collects in the space.
Crawl Space Vapor Barrier - A Beginner's Guide On Buying The Right One
A crawl space dig out is the process of turning your crawl space into a basement. This vastly increases storage space and can, in some cases, increase living space as well.
But, a crawl space dig out can be an enormous and daunting task. And, if done improperly, it can be dangerous. If you don't want to have a professional do it for you, please follow the steps below.
To get started, find place in the outside wall of your crawl space that you can safely enter the new basement with a temporary or permanent set of steps. Make sure the wall opening is big enough to handle at least a 36-inch door, preferably making the area for the steps at least 48-inches wide.
Warning:
If your soil is sandy or gravel and or may be full of water at least part of the year do not consider this procedure, it is very dangerous and you may damage or lose your house.
Make sure that prior to digging the hole for the outside exit, please build a header of sufficient size to hold the floor of the home where you will be removing the old foundation.
You need to excavate to a depth that will accommodate a four-inch concrete slab and still have at least 7-foot, 6-inches of clearance under your floor joist. It is entirely possible that you will have 48 inches of soil to remove.
When digging out a crawl space, you can not excavate any closer than 24 inches away from the existing foundation.
You can remove the soil sufficiently to work along the wall without removing the entire area you wish to change.
When you get the soil out to a depth that you prefer, pour a footer that is eight inches thick and 16 inches wide. The footer should be below the bottom of the new slab so it is a good idea to dig the area for the footer below the level you remove for the floor area. This is a very important step in a crawl space dig out.
Then, when your block is level with bottom of the old foundation wall you need to pour a four-inch thick slab of concrete on top of the wall and over to the outside existing wall.
Prior to pouring your "Cap" you must fill between the block and soil that is under the old foundation with fill sand or "Pea-gravel." Assuming that you probably have some kind of support under the center section of the floor system, you will have to provide support for the beam that is presently supporting the floor while excavate for a new footer for a steel post that will hold the floor of your new space.
Make sure your footer for this part of the project is about eight inches thick & 24 inches square.
You will need to level the floor area for your new slab and install four inches of perforated plastic pipe draining to a sub pit with an automatic sub pump that dispenses the water to the outside at least five to ten feet away from the foundation of the home. I'd suggest using "Pea-gravel" for fill under the slab but you can you fill sand also.
Now, build your stairs to the outside in a similar fashion but you need to cover it with a steel "pre-fab" unit such as a "BILCO."
If you do this correctly and maintain it, it will last for many, many years. It is strongly suggested you get a professional to do this job or at least help with it because mistakes can be dangerous and very costly.
A Closed, Sealed Crawlspace - What a Really Bad Idea
The crawl space has an integral role towards a home's overall value as well as the living space above. Most homeowners don't think twice about their crawl space unless they have to make repairs to plumbing, heating ducts or house wiring. While often thought of as no more than a storage area, it also has a tremendous impact on the overall indoor air quality of the entire home.
By default, the air quality of a crawl space is typically poor. Mold, mildew, radon gas and poor energy efficiency all create several problems. The air that circulates within it eventually makes its way up through the living space. Scientific studies show that up to 50% of living space air originates from the lowest level of the home. With homeowners more concerned about their home's indoor air quality, the encapsulating of crawl spaces has become a popular solution for such problems.
A damp crawl space creates a safe harbor for harmful molds, in addition to dust mites, termites and other bugs that can infest the home. The presence of excessive moisture will also create a serious problem with the probability for the wooden structure of a home to deteriorate. Crawl space vents pose a further problem. While believed to be a solution to moisture problems, they unfortunately make the problem worse. As it turns out, the vents allow cold air and moisture in, which rises into the living area and therefore decreases the heating efficiency of the entire home.
Another all-too-common problem associated with crawl spaces is radon gas. Though it cannot be seen, smelled or tasted, radon is a radioactive gas that can contribute to poor health, including cancer. Radon gas makes its way through the earth, into the crawl space and the home's living space. According to the U.S.E.P.A., radon gas is the number one leading cause of lung cancer in non-smokers.
Ignoring these various conditions is not recommended for both long-term health and energy usage. Fully encapsulating a crawl space - by both sealing and insulating - is a fully efficient measure in addressing such problems. It makes sense to maintain and improve the lower level area in order to maximize healthy living conditions and home resale value.
While there are several systems for encapsulatiing, a zero perm liner system that also insulates and reflects heat provides the most benefits. With a proper floor and wall liner, the area will not only be well insulated, but will seal out moisture, bug infestation and radon gas. Other components to look for in a system include a radon gas-dispersing drain fabric, a radon gas ventilation pipe and a ceiling heat shield.
A complete system with all of the above components will allow any soil gases - including radon gas - that naturally occur under the liner system, to wick through the drain fabric and escape out through the ventilation pipe. While improved indoor air quality is the primary benefit of a sealed and insulated crawl space, the homeowner will also appreciate a bright, clean, and dry storage area; the ridding of musty smells; less energy usage; and tax credits. Contractors encapsulating crawl spaces will have more to offer to their clients when they can assure the peace of mind with improved indoor air quality.
